#include <stdio.h> #include <stddef.h> #include <signal.h> #include <unistd.h> #include <sys/wait.h> int system(command) char *command; { int wait_val, pid; __sighandler_t save_quit, save_int, save_chld; if (command == 0) return 1; save_quit = signal(SIGQUIT, SIG_IGN); save_int = signal(SIGINT, SIG_IGN); save_chld = signal(SIGCHLD, SIG_DFL); if ((pid = vfork()) < 0) { signal(SIGQUIT, save_quit); signal(SIGINT, save_int); signal(SIGCHLD, save_chld); return -1; } if (pid == 0) { signal(SIGQUIT, SIG_DFL); signal(SIGINT, SIG_DFL); signal(SIGCHLD, SIG_DFL); execl("/bin/sh", "sh", "-c", command, (char *) 0); _exit(127); } /* Signals are not absolutly guarenteed with vfork */ signal(SIGQUIT, SIG_IGN); signal(SIGINT, SIG_IGN); #if 0 printf("Waiting for child %d\n", pid); #endif if (wait4(pid, &wait_val, 0, 0) == -1) wait_val = -1; signal(SIGQUIT, save_quit); signal(SIGINT, save_int); signal(SIGCHLD, save_chld); return wait_val; }